A systematic guide to assessing hemorrhage, ischemia, mass effect, ventricles, and osseous structures on emergency and routine noncontrast head CT examinations.
RadPhrases Editorial Team5 min read
A systematic guide to assessing hemorrhage, ischemia, mass effect, ventricles, and osseous structures on emergency and routine noncontrast head CT examinations.
Scope The following is a general review sequence for standard adult noncontrast head CT. Stroke protocols, CT angiography/perfusion, trauma-specific facial or temporal bone examinations, pediatric neuroimaging, and postoperative cases require additional expertise.
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The greatest advantage of noncontrast head CT is speed; the greatest risk is missing a small but important finding while reading too quickly. Using the same window settings and anatomical sequence facilitates safer assessment of acute hemorrhage, early ischemia, and signs of herniation, particularly during on-call work.
The following checklist does not replace image interpretation. Its purpose is to confirm, before signing the report, that all critical anatomical regions and the clinical question have been addressed systematically.
1. Request, protocol, and image quality
☐ Clarify the clinical question. Trauma, acute neurologic deficit, headache, altered consciousness, seizure, and postoperative assessment create different priorities.
☐ Confirm that the examination is truly noncontrast. Recently administered contrast may affect appearances such as subarachnoid hemorrhage or dural venous sinus density.
☐ Check coverage. The entire cranium and brain parenchyma from the foramen magnum to the vertex should be included.
☐ Assess motion and metal artifact. Reflect any limitation, particularly in the posterior fossa and skull base, in the report.
☐ Open prior imaging. Comparison may be critical for chronic collections, ventricular size, and postoperative changes.
2. Use window settings deliberately
☐ Brain window. Assess parenchymal attenuation, gray-white differentiation, edema, and mass effect.
☐ Subdural/wide window. Improve detection of thin extra-axial hemorrhage and hyperdensities adjacent to dense bone.
☐ Bone window. Perform a separate review for fracture, lytic or sclerotic lesions, pneumocephalus, and skull-base structures.
☐ Narrow window settings when needed. Optimize workstation settings for the clinical question, particularly for early ischemia or posterior fossa assessment.
3. External soft tissues, calvarium, and skull base
☐ Scalp. Is there a hematoma, laceration, foreign body, or subcutaneous emphysema?
☐ Skull. Check for linear or depressed fracture, sutural diastasis, and postoperative defects.
☐ Skull base. Look for fracture signs together with sphenoid sinus fluid, mastoid opacification, and pneumocephalus.
☐ Orbits and visible facial bones. In trauma or when clinically suspected, assess the visible structures despite limited coverage.
4. Survey for acute hemorrhage
☐ Extra-axial spaces. Review the convexities, fissures, and basal cisterns for epidural, subdural, and subarachnoid hemorrhage.
☐ Parenchyma. Assess for hyperdense foci in the lobes, deep gray nuclei, brainstem, and cerebellum.
☐ Ventricles. Check for intraventricular blood, fluid-blood levels, and signs of obstruction.
☐ Effect of hemorrhage. Describe volume, surrounding edema, sulcal effacement, midline shift, and signs of herniation.
☐ Hemorrhage mimics. Differentiate calcification, dense vessels, residual contrast, and artifacts in the clinical context.
5. Ischemia and parenchymal symmetry
☐ Gray-white differentiation. Check the insular ribbon, lentiform nucleus, and cortical ribbons for asymmetry.
☐ Focal hypoattenuation. Assess vascular distribution, conspicuity of margins, and whether volume loss is present.
☐ Hyperdense vessel sign. Compare visible arteries in the appropriate clinical context and remember that this sign alone is not diagnostic.
☐ Posterior circulation. Review the brainstem and cerebellum separately and slowly despite beam-hardening artifact.
☐ Chronic changes. Distinguish old infarcts, encephalomalacia, lacunes, and chronic microvascular change from acute findings.
6. Mass effect, ventricles, and cisterns
☐ Sulcal appearance. Focal or diffuse effacement may indicate edema, mass effect, or diffuse cerebral swelling.
☐ Midline. Assess shift at the septum pellucidum and third ventricle; if measurement is needed, use a consistent method.
☐ Basal cisterns. Check patency, asymmetry, and signs of herniation.
☐ Ventricular size. Is there hydrocephalus, asymmetry, transependymal flow, or a change from the prior examination?
☐ Extra-axial CSF spaces. Distinguish atrophy from subdural collection and assess the attenuation and membranes of chronic collections.
7. Vessels, sinuses, and additional structures
☐ Major vessels. Note visible abnormalities such as marked hyperdensity, aneurysmal contour, or gas, while stating that noncontrast CT does not replace CT angiography.
☐ Dural venous sinuses. Consider venous thrombosis when there is asymmetric hyperdensity or appropriate clinical suspicion; discuss suitable further imaging with the clinical team when necessary.
☐ Paranasal sinuses and mastoids. Record acute fluid levels, marked opacification, or osseous change in the clinical context.
☐ Sella and craniocervical junction. Is there an obvious mass or evidence of tonsillar herniation within the imaged structures?
8. Order of priorities in the impression
State life-threatening acute findings in the first sentence, such as hemorrhage, herniation, hydrocephalus, or a large acute infarct.
Summarize the finding with location, type, size or effect, and interval change.
Answer the clinical question; for example, do not use “no acute intracranial hemorrhage” without qualification when the examination is technically limited.
When needed, phrase recommendations for further imaging or clinical correlation in a way that reduces uncertainty.
Communicate urgent findings directly according to the local critical results policy and document the communication.
Communication of critical findings
Time-sensitive findings For acute intracranial hemorrhage, herniation, substantial mass effect, acute obstructive hydrocephalus, findings suspicious for large-vessel occlusion, or other conditions that may deteriorate rapidly, activate the institution's urgent communication pathway without waiting for final report sign-off.
9. Commonly overlooked areas
Thin convexity subdural collections
Interhemispheric fissure and tentorium
Small-volume subarachnoid blood in the basal cisterns
Posterior fossa and brainstem
Small contusions at the vertex
Skull base and temporal bone region
Small interval changes in ventricular size
Extracranial traumatic findings
10. Example report framework
INDICATION: [Acute neurologic deficit / trauma / headache / other] TECHNIQUE: Noncontrast head CT. [State any artifact/limitation]. COMPARISON: Compared with the examination dated [date] / No comparison available. FINDINGS: - Acute intracranial hemorrhage: [none / type and location] - Gray-white differentiation and parenchyma: [...] - Mass effect / midline / basal cisterns: [...] - Ventricles and extra-axial CSF spaces: [...] - Calvarium and skull base: [...] - Imaged sinuses/mastoids/orbits: [...] IMPRESSION: 1. [Acute critical finding or answer regarding acute intracranial abnormality.] 2. [Important chronic/secondary finding, if present.]
References
ACR Practice Parameter for Communication of Diagnostic Imaging Findings, Revised 2025. Report components and principles for nonroutine/urgent communication. Source (opens in a new tab)
ACR-ASNR-SPR Practice Parameter for the Performance of CT of the Head, Revised 2025. Framework for head CT performance, documentation, and safety. Source (opens in a new tab)
ACR-SPR Practice Parameter for Performing and Interpreting Diagnostic CT, Revised 2022. General principles for CT performance, interpretation, and documentation. Source (opens in a new tab)
Clinical use note
This content is educational and is not patient-specific medical advice. Every phrase, template, classification result, and recommendation must be verified and adapted by a physician using the complete examination, clinical context, current guidelines, and institutional protocol.
Turn the checklist into a report template
Use this sequence as an editable RadPhrases template and verify it against the images in every case.
